A rectangular-core (ribbon) fiber that guides and amplifies a single higher-order-mode (HOM) can potentially scale to much higher average powers than what is possible in traditional circular-core ...large-mode-area fibers. Such an amplifier would require mode-conversion at the input to enable interfacing with seed sources that typically output TEM(00) mode radiation and at the output to generate diffraction-limited radiation for end-user applications. We present the first simulation and experimental results of a mode conversion technique that uses two diffractive-optic-elements in conjugate Fourier planes to convert a diffraction limited TEM(00) mode to the HOM of a ribbon fiber. Mode-conversion-efficiency is approximately 84% and can theoretically approach 100%. We also demonstrate a mode-converter system that converts a single HOM of a ribbon fiber back to a diffraction-limited TEM(00) mode. Conversion efficiency is a record 80.5%.
The intrategumental pH in adult male Schistosoma mansoni as measured with pH-sensitive microelectrodes is between 7.0 and 7.2, a value about one pH unit more alkaline than expected for equilibrium. ...This value is maintained for at least 4 h after isolation in media buffered with Hepes or CO2/HCO3- with or without serum present. CCCP (1 microM) and FCCP (10 microM) cause rapid acidification. DNP (1 mM) and Na-orthovanadate (1 mM) acidify but also cause significant depolarization of the tegument. NH4+ (20 mM) depolarizes and acidifies the tegument with no evidence of transient alkalinization. High K+ (25 mM) accelerates the acidification. Removal of the NH4+ causes a large transient further acidification with recovery requiring as long as 40 min. High K+ (25 mM) delays the early stage of the recovery. Presence of CO2/HCO3- in the incubation medium does not accelerate the recovery rate nor does SITS (100 microM) inhibit the recovery. Intrategumental Na+ is elevated after an acid load and amiloride (3 mM) as well as low Na+ medium interfere with recovery from the acid load indicating that a Na(+)-H+ exchanger may be present in the tegumental membrane.
A Nd
fiber amplifier with gain from 1376 nm to 1466 nm is demonstrated. This is enabled by a wavelength selective waveguide that suppresses amplified spontaneous emission between 850 nm and 1150 nm. ...It is shown that while excited state absorption (ESA) precludes net gain below 1375 nm with the exception of a small band from 1333 nm to 1350 nm, ESA diminishes steadily beyond 1375 nm allowing for the construction of an efficient fiber amplifier with a gain peak at 1400 nm and the potential for gain from 1375 nm to 1500 nm. A peak small signal gain of 13.3 dB is measured at 1402 nm with a noise figure of 7.6 dB. Detailed measurements of the Nd
emission and excited state absorption cross sections suggest the potential for better performance in improved fibers. Specifically, reduction of the fiber mode field diameter from 10.5 µm to 5.25 µm and reduction of the fiber background loss to <10 dB/km at 1400 nm should enable construction of an E-band fiber amplifier with a noise figure < 5 dB and a small signal gain > 20 dB over 30 nm of bandwidth. Such an amplifier would have a form factor and optical properties similar to current erbium fiber amplifiers, enabling modern fiber optic communication systems to operate in the E-band with amplifier technology similar to that employed in the C and L bands.
Several somatic illnesses are associated with psychiatric comorbidity. Evidence is provided that availability of the essential amino acid tryptophan, which is the precursor of serotonin, may cause ...this phenomenon.
We performed a database search to find relevant articles published between 1966 and 2002. For our search strategy, we combined several diseases from the categories hormonal, gastrointestinal, and inflammatory with the search terms "tryptophan" and "serotonin."
The catabolism of tryptophan is stimulated under the influence of stress, hormones and inflammation by the induction of the enzymes tryptophan pyrrolase (in the liver) and IDO (ubiquitous). Because of the reduction in blood levels of tryptophan under these circumstances the formation of cerebral serotonin is decreased.
It is argued that the coupling of peripheral tryptophan levels and cerebral serotonin levels has physiological significance. The clinical implications and therapeutic consequences of changes in tryptophan and consequently serotonin metabolism are discussed.
Introduction/Aims
There is debate about whether and to what extent either respiratory or cardiac dysfunction occurs in patients with dysferlinopathy. This study aimed to establish definitively ...whether dysfunction in either system is part of the dysferlinopathy phenotype.
Methods
As part of the Jain Foundation's International Clinical Outcome Study (COS) for dysferlinopathy, objective measures of respiratory and cardiac function were collected twice, with a 3‐y interval between tests, in 188 genetically confirmed patients aged 11–86 y (53% female). Measures included forced vital capacity (FVC), electrocardiogram (ECG), and echocardiogram (echo).
Results
Mean FVC was 90% predicted at baseline, decreasing to 88% at year 3. FVC was less than 80% predicted in 44 patients (24%) at baseline and 48 patients (30%) by year 3, including ambulant participants. ECGs showed P‐wave abnormalities indicative of delayed trans‐atrial conduction in 58% of patients at baseline, representing a risk for developing atrial flutter or fibrillation. The prevalence of impaired left ventricular function or hypertrophy was comparable to that in the general population.
Discussion
These results demonstrate clinically significant respiratory impairment and abnormal atrial conduction in some patients with dysferlinopathy. Therefore, we recommend that annual or biannual follow‐up should include FVC measurement, enquiry about arrhythmia symptoms and peripheral pulse palpation to assess cardiac rhythm. However, periodic specialist cardiac review is probably not warranted unless prompted by symptoms or abnormal pulse findings.
Based on previous evidence suggesting abnormalities in the brain microvasculature, we examined basement membrane collagen in isolated cerebral microvessels (CMV) from subjects with Alzheimer's ...disease (AD) and age-matched controls. Concentrations of hydroxyproline, the principal constituent of collagen IV, were significantly increased by 55% in CMV from AD subjects compared to controls. This result was corroborated by the finding of 60% increased total collagen content in CMV as evident by the selective binding of Sirius red dye. Hydroxyproline and collagen concentrations in samples of cerebral cortex assayed in parallel were 6–20 times smaller than in CMV and were not changed between controls and AD subjects. To further differentiate AD and control samples, fractions of CMV were solubilized and the pepsin digested collagen proteins resolved by SDS-PAGE. Upon immunoblotting, AD samples with increased collagen revealed proportionally greater specific immunoreactivities detected by antibodies to collagen IV. Our observations suggest altered collagen IV content of cerebral vessels in subjects with AD that may affect brain microvascular functions.
An apparent ion channel with a conductance of 295 pS is present in isolated inside-out patches of outer tegumental membrane taken from female Schistosoma mansoni. With positive voltages applied to ...the intracellular face of the patch, percentage open time for the channel was 0 to 50; with negative voltages applied, percentage open time was greater than 99. Step changes in applied voltage characteristically induced opening-closing activity. However, there was no maintained applied voltage at which there was a high level of sustained opening-closing activity. The 295 pS conductance was by far the most commonly occurring conductance but it appears to result from cooperativity among several channels, the unitary conductance for the channel averaging 95 pS. Alterations in the Na+ or K+ concentration ratios changed the reversal potential for this conductance but alterations in the Cl- concentration did not. From this it is concluded that this channel is selective for Na+ or K+ over Cl- and it appears to be a nonselective cation channel.
The phorbol esters, phorbol-12,13-dibutyrate, phorbol-12-myristate-13-acetate, phorbol-12,13-didecanoate, and phorbol-12,13-diacetate, as well as mezerin at concentrations as low as 10 nM produce a ...spastic paralysis of the schistosome musculature. The action of these protein kinase-C activators is dependent on the sites of esterification and is stereo-specific since phorbol-13,20-diacetate, phorbol-12,13,20-triacetate, 20-oxo, 20-deoxy-beta-phorbol-12,13-dibutyrate, alpha-phorbol-12,13-didecanoate, and alpha-phorbol are inactive. A phospholipid and phorbol ester-dependent protein kinase is identified. This kinase is stimulated by all of the phorbol esters that increase muscle tone but is not stimulated by phorbol esters that do not affect muscle tone. A high affinity, stereo-specific phorbol ester receptor is identified. Dose-response curves of phorbol-12,13-dibutyrate-induced muscle tension and -stimulated kinase activity and receptor binding indicate that these responses are mediated by the same system. These results indicate that protein kinase-C-like enzyme may play an important role in modulating activity of the schistosome musculature.
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